Crown cap and apparatus for forming same



July 21, 1936. J D E 2,048,062

CROWN CAP AND APPARATUS FOR FORMING SAME Filed June T 1932 2 Sheets-Sheet l July 21, 1936. i A .v 1.. D. ELDER i; I 04 0 @ICROWN CAP AND APPARATUS FOR FORMING SAME I Filed Jun 7, 1932 2 Sheets-Sheet 2 jjgi gwoehtoz Jam 2. ZZde/l may Patented July 21, 1936 UNITE STATES PATENT oF cE CROWN CAP AND APPARATUS FOR.

romvnnc. SAME Application June 7, 1932, Serial No. 615,910

1 Claim.

The present invention relates to improvements in crown caps and in apparatus for the production of the improved caps.

The principal purpose of the, invention is to 5 provide a cap more economical to produce than comparable caps of the'prior art, but fully as effective, or more so, as regards sealing capacity, the new cap being particularly designed for application to containers for beverages under pressure. In the manufacture of the new cap, economies are efiected in that it may be produced from lighter gauge metal than heretofore possible, it requires a smaller blank, and enables a thinner sealing gasket to be used.

5 Experiments with a view to reducing the'size of the blank required for the ordinary crown cap have shown that no substantial reduction can be made without undue loss in sealing capacity. In order to reduce the size of the blank, the re- .0 duction must occur in the skirt and flange portions' of the completed cap, since the diameter of the cap is determined by the standard size. of container opening. With the shallower skirt portion and the thinner gasket necessitated thereby,

:5 it has been impossible, for various reasons, to effect a satisfactory seal especially for containers for pressure beverages and the like. By shallower skirt, I mean relative to the standard crown.

In applying the crown cap of ordinary design 30 to a beaded bottle opening, the gasket is initially compressed by a spring pressed stripper foot which bears against the top of the cap. A sealing throat, ordinarily tapered, engages the lower edge of the skirt upon axial displacement rela- 35 tive to the cap, and by a substantially radial compressive action wedges the lower portions of the cap flutings under the bead. This action results in some further compression of the gasket and provides the locking engagement with the bead.

In the application of the cap of the present invention to a beaded container opening, a radically different action is obtained by reason of the particular design of the cap. According to the present invention, the cap has a relatively shallow 45 skirt portion which is cylindrical and smooth, that is, free of corrugations or flutings. The skirt portion terminates in an outwardly directed relatively narrow circumferential locking flange comprising substantially plane portions joined 50 by substantially V-shaped ridges which project upwardly or toward the top of the cap, the ridge lines being substantially parallel to the plane portions. By relatively narrow locking flange, I mean a locking flange of less overall width in 55 relation to the overall width of, the flared portion of the standard crown. More particularly, the plane portions lie in a common plane normal to the axis of the skirt portion and the ridge lines are substantially radial to the skirt portions except, of course, at their inner extremities where 5 they round into the skirt.

In the application of the new cap to a beaded opening, the sealing gasket, which need be no more than half the thickness of the usual gasket and thus permits the shortending of the skirt, is initially compressed, as before, by the stripper foot. This action of the stripper foot, however, is of relatively little importance in this instance. The sealing throat, which is interiorly cylindrical, has an annular plain abutment surface. normal to its axis which squarely engages the locking flange of the cap and carries the cap downwardly, compressing the sealing gasket, until the tops of the ridges come substantially to or slightly below the maximum circumferential lines of the bead. Hereupon the flange is bent inwardly, the skirt portions between the ridges taking a knee formation in contact with the bead below its maximum circumference, these knees constituting the fulcrums of what are in effect levers of the second class so that as the flange moves under the bead the cap is subjected to'a powerful drawing action, conforming it closely with the upper lateral surface of the bead exterior and highly compressing the entire portion of the gasket overlying the bead. At the completion of the operation the flange lies beneath the head with the plane portions thereof within the projection ofthebead and the ridge lines substantially vertical and in the projection of the skirt portion. As the flange is bent beneath the bead, the walls of the respective ridges are brought together, or substantially so, so that the plane portions become almost continuous circumferentially of the cap as does likewise the lower marginal portion of the skirt into which the ridges merge, and which engages the bead of the container below the maximum circumference of the bead.

The above described levering action has a reaction outwardly and radially of the skirt as well as the main axial drawing effect. This reaction is resisted by the sealing throat in the case of close contact of the latter with the skirt and is also effectively resisted by the skirt itself which is free of corrugations which would tend to straighten out. The smooth skirt of course continues to resist any radially expansive tendency of the easily counteracted by the knee portions due to the locking position which they assume wherein the respective fulcrum points and load. sustaining points are in lines at acute angles to the vertical with the latter points below the former as will be more fully explained hereinafter. This disposition, together with the substantially con-= tinuous circumferential locking grip, so enhances the sealing capacity that the gasket is held in fully compressed condition even against unusually high pressure within the container. The improved locking efiect is such that a relatively light weight metal may be used in the manufacture oi the cap. I

The invention also includes apparatus for the production of the improved cap above described.

Without further general discussion of the in vention, I shall proceed to describe it with reference to the accompanying drawings, wherein:

Figure l is an enlarged plan view of a cap of the form contemplated under the present invenion.

Figure 2 is an elevation of the cap of Figure l as applied to the mouth of a'container, here shown as a bottle.

Figure 3 is an elevation of the cap of Figure l.

Figure 4 is a plan view of a slightly modified form of cap.

Figure 5 is an elevation of the cap of Figure ies applied to the mouth of a bottle;

Figure 6 is an elevation of the cap 'of Figure 4.-

v-shaped upwardly projecting ridges 26, the ridge lines or lines of intersection of the ridge walls 7 being substantially radial to the axis of the skirt portion so that the ridges are of uniform height. There is, of course, some deviation from the ra-' dial direction of these ridge lines where they round into the lower marginal portion of the skirt, this lower marginal portion presenting serrations 23' caused by the ridges 26. The skirt portion is rounded into the top surface 2i so as to conform Substantially to the shape of the usual head or locking flange which is shown for example in Figures 7 to 10 at '65, the bead surmounting the longitudinal movement is eflected between the bottle and a sealingthroat 29, the initial posi tion of the parts being shown in Figure 7. As may be readily seen from this figure, the flange 2a in the initial position is somewhat above the line of maximum circumference of the head 65.

In applying the cap the compressive action of the Y stripper foot zs'may be considered as being more or less incidental, since even in its absence complete compression of the gasket 28' will be secured. When the stripper foot is used, it acts on the top of the cap to compress the gasket until the lower As here plane surfaced edge of the cylindrical sealing throat 29 strikes flange 24. When this occurs, there is an immediate tendency for the flange 26 to move inwardly, this tendency, however, being restrainedby contact of the inner surface of the 5 shell with the bead 65, Figure 8, by the sealing throat which restrains the consequent outward reaction of the shell above its line of contact with the bead, and by the inherent rigidity of the flange itself which is reinforced by the ridges of 10 substantially uniform height; As a result, the whole cap is carried downwardly by the sealing throat until the tops of the ridges 26 come to or slightly below the line of maximum circumference of the bead, whereupon the portions 23' of the lower skirt margin, and the flange 2t, begin to move under the shoulder of the bead, this being shown in Figure 9. The portions 23' dispose themselves as knees beneath the shoulder and constitute fulcrum points of lever-like formations which in the relation of parts shown in Figure 9 may be considered to occupy essentially positions as indicated in dotted lines at i. The outer ends of these levers are at the point of engagement of the throat with the ridges 25, the tension-exerting portion of the levers being between the ends thereof. A

' As the throat continues to descend, the levers are caused to approach the vertical and as they swing under the bead to the position of Figure 10, 30

a powerful drawing action is exerted on the skirt so that the gasket is still further compressed. j The drawing action brings in the angle between the cap skirt and top and in so doing; the marginal portion of the gasket is highly compressed between the cap and the side of the head, this being a place where very little, if any, sealing effect is secured with the ordinary cap. Thus, as distinguished from the old cap, the new cap aifords a tight seal throughout the entire portion of the '40 gasket which overlies the bead.

As the flange 24 moves under the bead, an outward reaction occurs above the maximum circumferential line of thelatter, this reaction being counteracted by the throat and also by the smooth skirt which offers great resistance to the reaction due to its lack of corrugations. In Figure 10, the lines of the levers I have more or less approached, the vertical with the points of load sustention below the fulcrum points so that a great mechanical advantage exists as against upward stresses acting on the cap.

In being forced from the position of Figure 8 to that of Figure 10, the flange 26 has been combead and this radial compression results in the I crimping of the ridges 26 so that their respective walls substantially come together and their crests come substantially into the projection of the cylindrical skirt portion as clearly shown in Figure 10. In this operation the plane portions 25 undergo no distortion, or substantially none, the contraction being taken by the crimped ridges. The plane portions 25 now Iiewithin the projec-- tion of the bead, and due to the close relation into which the wallsof the crimps have been brought, are substantially continuous circumferentially of the cap. Due to the close relation of the walls of the individual crimps, portions 23' of the skirt as well as portions 250i the flange become circumferentially substantially continuous, so that an almost continuous grip is obtained beneath the bead, and a most effective locking thus secured.

The ca shown in Figures 4 to 6 isfundamenaocaoca tallythesameasthatshowninflgureslto3,the diflerence being that according to Figures 4 to 6, theplane portions 25' of the flange have individually a greater circumferential extent than the plane portions 25 of Figures 1 to-3. This means that the number of ridges and plane portions is reduced as compared to the flrst described embodiment. As here shown, flange 24 of the cap of Figure 1 is provided with twenty-four ridges 26, while flange 24' of cap 20' of Figure 4, has only sixteen ridges 26'. It will be evident that, upon application of the cap of Figure 4, the walls of the crimpedpridges 26' will be brought closer together than the walls of the crimped ridges 26, and the number 'of ridges might be so chosen that their respective walls, upon application of the .cap, would be brought entirely together.

However,in practice, twenty-two or twenty-four ridges have been found most satisfactory,and any suitable number may be used so long as the final effect above described and discussed is substan; tially obtained.

Hence, as shown in Figures 3, 6, and 8 particu- I larly, the sharp right angle bend of the joint between the skirt and the circumferentialflange 24 with its plane portions and ridges, causes the flange to bend or fulcrum in a plane immediately at the top of the ridges. Due to'this, the depth of the skirt can be kept at a minimum and because the width of the flange is stillconsiderably less than the depth of the skirt, a great saving in metal results. In other words, the radial length of the ridges is less than the distance from the tops of the ridges to the top of the cap as shown in Figures 3 and '6 for example, and there results an enhanced sealing eifect, together with a drawing down of the skirt, and particularly of the sealing liner, as shown in Figures 21 and 25 whereby the sealing lineris drawn down in substantially conforming relation to the upper outside of the sealing surface'of the container.

The new cap accommodates itself readily to. either a minimum or maximum bead and to any bead within these limits. with the maximum bead 45, for example, shown in Figures '1- to 10, the steps are the same as with a minimum bead. However, with a minimum head, the lines of the ridges come substantially below the shoulder of the bead, whereas according to Figure 8, these lines are somewhat above the shoulder. Substantially the same knee or lever action occurs with a minimum or maximum bead, as shown in Figure 9, so that the final result shown, fopexample, in Figure 10, is substantially the same with either type of head. In the case of a minimum head, the upper ends of the crimps often come in below the head so that the bottom of the skirt is continuously curved under the shoulder throughout its circumference. While this exact conformation is not obtained with a maximum head, the locking effects are substantially thesame.

From the above disclosure it will be understood that the present invention makes possible the saving of a considerable amount of metal in view of the smaller sized blank required, and, moreover, the metal may be of lighter gauge than ordinarily in view of the improved locking action obtained. The saving in gasket material may be at least flfty per cent as regards thickness, and a side seal is obtained between the bead and cap 7 limit myself exactly to the details shown and 20 described, since variations are possible without departure from the scope of the invention as defined in the following claim.

I claim:

A crown cap provided with a sealing liner hav- 25 ing a substantially smooth cylindrical skirt relatively shallow as compared with the standard crown cap and terminating downwardly in an outwardly and radially directed relatively narrow circumferential flange extending at substantially 30 right angles to the vertical axis of the cap, said 'flange having an overall width less than the overall flare of the standard crown cap, the flange being provided with'a plurality of spaced ridges and the joint between the top edges of the ridges and the skirt defining a sharp right angle bend and said ridges being of a length considerably less than the distance from the tops of the ridges to the top'of the cap. the flange portions between said ridges being plane and the joint between said plane portions and the skirt-also defining a sharp I right angle bend, said ridges when the cap is api plied to a container forming levers and the adjacent circumferential portion of the skirt constituting a fulcm:--. whereby the plane portions are brought within the projection of the largest diameter of the sealing bead of the container and the top edges of the ridges occupy a vertical position parallel to the axis of the cap substantially within the projection of the skirt of the cap, and with the ridge walls collapsed together, the lever action created by the cooperation of the ridges with the adjacent circumferential portion of the skirt producing a downward sealing pressure distributed uniformly throughout the area of the skirt and acting to draw the skirt downwardly and the sealing liner of the cap downwardly in substantially a conforming relation to the upper outside of the sealing surface.

JOHN D. ELD 

